


Boundaries

by paperfeathers



Category: Supernatural
Genre: FYSL Holiday Hellatus Fanwork Exchange, M/M, Masturbation, Nipple Play, Public Sex, Voyeurism, selfcest (of the Lucifer riding Sam variety)
Language: English
Status: Completed
Published: 2014-01-26
Updated: 2014-01-26
Packaged: 2018-01-10 02:11:20
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,511
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/1153530
Author URL: https://archiveofourown.org/users/paperfeathers/pseuds/paperfeathers
Summary: <blockquote class="userstuff">
              <p>In which Lucifer is a little shit, and Sam has absolutely no self-control. Poor Dean.</p>
            </blockquote>





	Boundaries

**Author's Note:**

  * For [Natt (lysanatt)](https://archiveofourown.org/users/lysanatt/gifts).



> For the FYSL Fanworks Exchange. 
> 
> Prompter: lysanatt (Natt on ao3)
> 
> Prompt used: “A hard fuck up against the wall/bed/any surface available, preferably in a situation where they can get discovered." I think I nailed the "situation where they can get discovered" part. :awkward cough: I hope you like it, dear!

Sam’s dozing in the Impala’s backseat when it happens. A sharp spike of alien energy rushing through his veins, concentrated light filling his cells. His eyes snap open and he almost cries out, but the sound of Lucifer chuckling has him muffling the sound behind gritted teeth.

_Lucifer, the hell?!_

_Hello to you too, Sam._ Lucifer’s grace brushes over him like a caress. In spite of himself it calms his earlier panic, and he settles back down. Surreptitiously glancing at Dean, but mercifully his older brother hasn’t noticed anything. Lucifer himself is little more than a murmur in the back of Sam’s mind, electricity dancing beneath his skin. 

_You know, an “I’m glad to see you.” would be nice._

_Sorry for being surprised, but I wasn’t exactly expecting you to jump my bones. Literally._ Lucifer huffs a little at Sam’s sarcasm. But the cool prickle of grace beneath his skin turns almostsoothing. In spite of himself, Sam smiles. It feels good, really good. Lucifer’s a supernova crouched behind his skin, all swiftly burning, radiant starfire. It should hurt, should strip him raw from the inside, but instead Sam always feels like he’s floating in a calm ocean of pure light.

_I heard that._ Lucifer murmurs. Grins using his lips and stretches. Sam feels his quiet curl of pleasure when the stiffness eases from his shoulders, skin sliding on the Impala’s soft, worn leather. When they’re together like this he’s always so much more tactile. Touching everything he can get his hands on: the cool metal of the Impala’s chassis and the sun-warmed roughness of road dust. A flower’s soft petals and the waxy smoothness of a leaf.  Right now one hand’s lingering on the edge of his smile, while the other slips under his shirt, tracing patterns on the skin of his chest.

_What’re you doing here, Lucifer? Did something happen to your old vessel?_  Lucifer shrugs.

_Nick’s as fine as a hollowed-out corpse is ever going to be._ Sam winces at that, and Lucifer pauses from tracing his lips to smooth out the wrinkle on his brow. _I wanted to see you. And since the sight of me brings out Dean’s… overprotective tendencies, I decided this would be the best way to get a little privacy._

_Privacy._ Sam says a little flatly. _You never bothered with that one before._

_Well, your brother has proven himself a spectacularly talented cock-blocker. Think of this as not-so-divine retribution._ The hand on his chest slips to one side. Fingers brush light and teasing at the nipple, rubbing lazy circles around the areola. Making Sam stiffen and his breath hitch.

_Lucifer…_ It’s a light growl of warning at the back of his mind.  But all protests die on Sam’s lips when he hears Lucifer laugh, soft and low and dirty. Gentle fingers rolling the hardened tip to delicious rawness and it’s all Sam can do to not moan aloud.

_Do you want me to stop, Sam?_ Lucifer’s voice echoing in his mind, warm and deep and rough. Heat flashes through his spine and deep into his core. And Christ, it’s a bad idea, it’s _such_ a bad idea. Dean would end him himself for how he’s about to _desecrate_ their childhood home. But Sam had never been able to refuse Lucifer anything after that first “Yes” -

_No._ Sam exhales shakily. _Keep going. And don’t you dare stop._

Lucifer smiles using Sam’s lips. Feral and hungry and altogether _depraved_ before going in for the kill.

It’s gentle at first. Sam shivers at feeling Lucifer through his own skin. Careful and curious. Lucifer’s touch is almost innocent as he traces every dip and curve, every scar marking his vessel. Quiet bliss and longing with every shifting press of skin. Then it becomes more insistent. The same blasphemous reverence is there, but now there’s that undercurrent of violence, that barely restrained _want_ that has Sam throwing his head back, face flushed. Grace prickles Sam’s fingertips as Lucifer uses them to map out Sam’s body. _Staking his claim,_ Sam thinks. In response Lucifer’s grip tightens.

_You have no idea how right you are._ The greed in Lucifer’s voice has him trembling. His fingers dig in his flesh harder, almost painful, making Sam’s breath come out in sharp, stifled gasps. But the heat pooling inside him is no match to the archangel crouched in his skin. Lucifer’s _burning._ Held together by the barest strands of furious control, but Sam can _feel_ him. Hotter than the heart of Heaven’s brightest star, colder than the deepest pit of Hell. Beneath Sam’s skin he’s radiant, incandescent. Holy fire and hell’s fury half-drowned in the skin and soul of a man. The thought of that should terrify him, struck him dumb with fear and awe. It shouldn’t make white-hot lust knife through his core at the sensation of the archangel losing himself to the ecstasy of human touch.

_Only for you, Sam._ Lucifer sounds just the slightest bit ragged. _Only for you._ He traces the outline of Sam’s tattoo, skin already damp with sweat before fingers drift back to Sam’s chest. Circling around the areola of his left nipple once, and this is all the warning Sam gets before Lucifer pinches the tip. Hard.

Somehow Sam manages to disguise the strangled cry that tears out of his throat as a cough. “You ok there, Sammy?” he hears Dean call out from the driver’s seat. He mumbles a reply, but it trails off to an barely inaudible gasp as Lucifer strokes the aching, hardened nub of flesh.  

_Christ! Lucifer, what the fuck?!_

_You feel good, Sam. So good._ Lucifer’s stroking a trail down his chest with one hand, the other hot and trembling as he starts in on the other nipple. But if before it had been gentle teasing this time it’s like he’s doing his utter damnedest to rip sound out of Sam’s throat. Every tug and light pinch going straight to Sam’s groin in time to the hard caress down his chest, ghosting near the ache between his legs. He bites back a groan, and never has he been more grateful for the Legos rattling in the Impala’s vents, and for Dean’s classic rock blasting through her speakers at full volume as Lucifer drifts down lower and lower –

_Lucifer…_ Sam gasps. Harsh and lewd and _far too loud_ in the Impala’s close confines. Belatedly he claps a hand over his mouth just as Dean switches off the music.

“… Sam?”

“Yeah?” In the back of  his head Lucifer is _snickering._ Sam would focus all his mental energies into glaring him into silence if he didn’t know it was a waste of time. Instead he focuses on stilling his hands where Lucifer’s inching his way towards the waistband of his jeans.

Dean doesn’t turn, doesn’t glance at Sam even through the rearview mirror (for which Sam’s grateful for). His hands are on the steering wheel, his eyes straight on the road. But his voice is calm. Dangerously calm.

“Baby’s almost out of gas. We’ll be pulling up at a gas station around ten minutes from here.”

“Oh. Uh. Ok?”

“It’s noon. Probably time to grab a bite, too.”

“….Ok?”

“Right.” Dean’s still poker-faced, but Sam can see his jaw twitching. “And Sam?”

“Yeah?”

“You know you’re my brother, right? And I’ve managed to abide by your life choices so far. Most of them, anyway. Your shitty taste in boyfriends included.”

“Uh…” Sam thinks he feels a tiny ripple of affront from Lucifer, but he’s entirely too focused on keeping his hands away from himself to pay much attention.

“But if the two of you are doing what I think you’re doing _in my car_ , I think it’s fair to warn you I have an archangel blade hidden somewhere. And next time I see Lucifer in his other vessel, I’m aiming for his dangly bits.”

“Uh… Sure.” Sam says a little faintly.

“You’d better be.”  Dean’s voice is still flat and calm. But he doesn’t say anything else, and right after his little speech he twists the radio dial back on, turning the volume up as high as it can go. Sam’s left facing the worn leather of the Impala’s  seat and Lucifer’s impish amusement.

_Are you trying to get an archangel blade shoved up your gut?!_ Sam hisses at him. Lucifer smirks.

_If big brother wants to watch so badly, then let him. In the meantime -_  One hand slides down to rest on top of his abdomen, lightly tugging at the trail of hair leading down.  Sam releases a shuddering breath. Grace flares deep within him, breathtakingly _hot._ In response Lucifer slides down lower, until Sam’s cupping his own length, straining beneath the rough fabric of his jeans.

_We’re not going to last much longer. Are we, Sam?_

_Fuck you._ Sam snarls. Breath coming out in muffled, uneven gasps, so far gone that he doesn’t even notice how Dean stiffens even further in the driver’s seat. Lucifer laughs, smug and unsteady.

_Maybe tonight. But right now  -_ he presses down, feeling the heat of it, the ache between their legs – _there’s something else that warrants our attention._

Before Sam can snarl out a reply the Impala stops. Dean’s barely managed to announce “We’re here.” before he’s stumbled out of  the car, so fast that he doesn’t even shut the door properly. Mindless of anyone and everyone else until he reaches the gas station’s bathroom. It’s completely empty, and Sam spares a second to wonder if maybe Lucifer had a hand in that before he slams the door shut and locks himself in.

He takes a moment to steady himself, hands gripping the sink. Lucifer smirks at him from the stained mirror.

_Well. That was fun, wasn’t it?_

“Screw. You.” Sam says it aloud, as emphatically as he can. Lucifer’s smirk only grows wider.

_Oh come on, Sam. Not like you hadn’t thought about it before. And you did enjoy your little payback._ Sam flushes, glares at him, but his reflection only smiles that infuriating little half-smile that never fails to enrage and arouse him in equal measure.

He’s still hard, his knees trembling so he has to grip one side of the porcelain sink to steady himself. Lucifer watches him hungrily as he unbuttons his jeans with shaking hands. The purr of the zipper goes straight to his spine, the rough friction of the denim on his over-sensitized flesh almost an agony as he pushes them down his legs. He straightens up, still half-supporting himself on one hand, facing the mirror. Lucifer’s hungry gaze roves down his form appreciatively. Sam sees his own chest heaving, and _god,_ he’s never looked more debauched. Flushed, half-undressed, hair a mess with his crooked shirt sticking to his sweat-damp body. His aching nipples rub against the coarse fabric, one more layer of sensation, and when Lucifer presses an open palm against  his stiff cock –Sam can’t help it, he groans.

Lucifer stares at him greedily from his reflection, mouth half-open with pleasure but with the edges still curled in a small smirk. The long, slow, careful drag against Sam’s cock nearly making Sam’s knees buckle beneath him. But he refuses to give in, to fall. Lucifer’s eyes glitter bright from the mirror, full of amusement, challenge, and lust. But Sam can feel the supernova spiraling out of control beneath his skin, and he knows Lucifer’s as close to giving in as he is, maybe even more.

_Really, Sam?_ Low and dark and sinuous, like a serpent of smoke. Squeezing hard at Sam’s length. Sam shivers and gasps, but doesn’t break eye contact with his lover. “I know you too well,” he pants, lifting an unsteady hand to his mouth, lightly wresting control from Lucifer. He keeps his eyes on the archangel as he coats his fingers with saliva. The salty tang of skin and the ozone taste of grace warring for dominance on his tongue. Lucifer’s eyes are half-lidded, but Sam can feel the tension wrapped around him as he sucks, bites, nips at his own flesh. Only when his hand’s well-coated and Lucifer’s thrumming like a live wire does he slip his erection free from his underwear, holding the weight and heat of himself in his hand.

Lucifer stills when he Sam wraps his damp hand around the base of his shaft, the tip glistening with pre-come. Eyes slipping almost shut as Sam begins stroking. Gentle and slow, always so gentle and slow at the beginning. But as Sam picks up speed his eyes fly open. Skin dragging against skin and heated friction. Before long, Lucifer’s gasping, exhaling sharply through Sam’s throat with every pull, every thrust through the damp, messy circle of Sam’s fingers.   

_Sam._ Lucifer’s gaze is wide. His mouth half-open, sweat trickling down his face and neck, down his collarbone. Arching into Sam’s hand as Sam works him, grip harsh and almost unforgiving as he strokes up and down. Like this, he looks nothing like an archangel, impassive and remote. All of humanity’s jagged edges and broken need are on his face, and he shudders. Tries to close his eyes. But Sam holds his ground, forces Lucifer to _look._ To watch himself shake apart at his own touch. Falling over and over again, but this time – this time Sam’s falling with him.

Sam feels something shatter with every thrust of his hips, every choked gasp he coaxes out of Lucifer. Feeling the boundaries of flesh, of touch, of self be erased with every shared cry of pleasure, every shared beat of pain as human desire and angelic grace coalesce into something bright and indefinable, indistinguishable. Lucifer looks lost, fragile and so, so _afraid_. But Sam’s there to murmur comfort, loving reassurance, even as fire licks them raw from the inside. Everything else obliterated but their touch their hands their body their self, rising higher only to be dragged down and sinking deeper only to be lifted up . Grace burning in their human veins, and eyes wide open and terrified but not, because where they’re going they’re going together and this is. This _is._

When they come, it is with one voice that they scream each other’s names.

Afterwards they lie slumped against the bathroom wall. Their body shivering, twitching, sweat cooling on their skin. Sam sees great arcs of broken light behind his eyelids as Lucifer whispers his name, over and over. One of them lifts their hand up, presses a light kiss on their wrist. Eyes on the mirror the entire time.

“We should get back… We’ve got miles to cover before the next hunt.” When Sam speaks, his throat feels raw. Lucifer shifts slightly against his soul, and Sam smiles at the grace brushing lightly against him. “Will you stay?” It’s soft, tentative. But Lucifer answers with a quiet flare of warmth.

_So long as you keep Dean from activating the banishing sigil he’s currently painting on your dashboard, I’m not going anywhere. At least -_ he stretches, and Sam feels his ripple of quiet joy and completion as his own .- _not for a while._


End file.
